1. Field of the Invention
The present invention relates to a baffle plate support structure for a transmission.
2. Description of the Related Art
In a casing of a transmission mounted on a vehicle, a baffle plate for reducing oil agitation resistance (stirring resistance) of gears is provided, for example, as described in Japanese Unexamined Patent Application Publication No. 2005-308044. The baffle plate is a plate-like member made of synthetic resin. The baffle plate is mounted such that it extends along the lower rotational periphery of gears and pulleys around rotating shafts. The baffle plate is composed of a series of curved surfaces that extend not only along the rotational periphery of gears, but also extend in a plane along the axial direction of the rotating shafts. Therefore, the baffle plate is a plate-like resin component having a relatively large area.
Such a baffle plate is provided with a support structure by which, in the casing of the transmission, both ends of the baffle plate are supported with respect to the inner surface of the casing. However, if both ends of the baffle plate are secured by tightening bolts etc. without play, vibration applied to the transmission while the vehicle is moving may cause resonance (surface vibration) of the baffle plate. This may lead to warpage of the baffle plate and shorten the vibration life of the baffle plate.
To prevent resonance of such a baffle plate in a known transmission, the baffle plate is secured by tightening bolts at one end only, and the other end of the baffle plate is provided as a free end not in contact with the casing, as described in Japanese Unexamined Patent Application Publication No. 2005-308044. That is, the support structure for the baffle plate provided here is a so-called cantilever support structure. However, if one end of the baffle plate is a free end which is not at all in contact with the casing, it is difficult to properly suppress excess vibration of the baffle plate.
In the cantilever support structure described in Japanese Unexamined Patent Application Publication No. 2005-308044, the free end of the baffle plate is covered with a transmission case. The free end of the baffle plate is located near the bottom inside the transmission case. This means that it may not be easy to check the mounting at the free end during assembly of the transmission. Therefore, it is difficult to add a support structure, which requires checking of mounting, to the free end of the baffle plate.
A manual transmission also has a baffle plate mounted inside the casing thereof. A baffle plate support structure used here is, for example, one that supports the baffle plate not by completely securing it to the casing at both ends, but by securing it to the casing with some play left therebetween (in a so-called floating state). However, use of such a support structure may result in insufficient mounting strength of the baffle plate. Moreover, since the amount of displacement associated with vibration of the baffle plate increases, it is necessary to leave a large clearance between the baffle plate and gears. This may hinder a reduction in size of the transmission. Additionally, significant vibration of the baffle plate and looseness of the support structure may cause noise.